1. Field of the Invention
The present invention relates to an air conditioning system. More specifically, the present invention relates to an air conditioning system with an energy recovery device that extracts work from expanding refrigerant moving from a high-pressure zone to a lower pressure zone of the air conditioning system.
2. Background Information
Air conditioning systems and heat pump systems are continuously being re-designed and modified in order to improve energy efficiency of such systems.
One such improvement is described in U.S. Pat. No. 6,272,871 wherein an air conditioning system is provided with an energy recovery device. The energy recovery device is basically a vane-type expander that is located downstream from a compressor (a high pressure zone) and downstream from an expansion valve. The energy recovery device is further located upstream from an evaporator (a low pressure zone) of the air conditioning system. High-pressure refrigerant from the compressor is released by the expansion valve and flows through the expander prior to reaching the evaporator. The expansion of the high-pressure refrigerant within the expander causes the expander to rotate, thereby producing rotary motion (work). The rotation of the expander can be used, for example, to provide supplemental rotary power to the compressor. Alternatively, the expander can be connected to a generator to produce electrical current.
The expander extracts work from the expanding refrigerant in a simple manner. The expander basically includes a housing having a chamber with an inner surface, a shaft mounted rotor within the chamber and a plurality of sliding vanes supported within slots in the rotor. The inner surface of the chamber is offset from the shaft that supports the rotor. The vanes can be biased by springs within the slot of the rotor to press against the inner surface of the housing chamber. As the rotor rotates, the vanes slide radially outward but are confined by the inner surface of the chamber. Since the shaft and rotor are axially offset from the center of the chamber, the volume of the space between any two adjacent vanes changes (increases or decreases) as the rotor rotates. The volume of the space between adjacent vanes proximate an inlet side of the chamber is smaller. The volume of the space between adjacent vanes proximate an outlet side of the chamber is larger. The expanding refrigerant migrates toward the outlet side rotating the rotor thus producing work.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved air conditioning system that further improves the operation and efficiency of air conditioning systems. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.